In early embryos, a concentration gradient of the Bicoid protein affects pattern formation. Studies of living embryos reveal a surprising level of accuracy in the Bicoid gradient. But is it accurate enough?rnA central idea in developmental biology is Lewis Wolpert s theory of positional information. This states that a substance present in a concentration gradient induces different developmental fates in cells when present at different concentrations. The first such morphogenetic rngradient to be identified was that of the gene transcription factor Bicoid in embryos of the fruitfly Drosophila melanogaster.
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